This invention relates to motor-driven pumps; more particularly the invention relates to a portable pumping system having capability for interchanging the driving source by utilizing a self-powered clutch for coupling between a reciprocable pump and any of a plurality of motor drive devices. The invention finds particular utility in portable pumping systems for which an electrical drive motor may be interchangeably used with an internal combustion drive motor, when external electrical power is not available. In such situations, the invention supplies its own electrical power needs to enable the drive motor to be efficiently coupled to a pumping system.
Prior art devices have included electrically-driven clutch assemblies in a common housing with an electrical generator; for example, U.S. Pat. No. 4,967,887, issued Nov. 6, 1990, discloses a magnetic particle clutch contained in the same housing as a permanent magnet generator, wherein the casing of the clutch is connected to a motor drive shaft and the rotor or disk of the clutch is connected to a load, and the rotor of the generator is also carried by the clutch casing; the generator produces an output voltage to power control circuitry for controlling the engagement of the clutch. The purpose of the patented invention is to provide an adjustable "soft start" to slowly bring the rotational speed of the load in synchronism with the speed of the drive motor.
In motor-driven pumping systems there is a need to control the action of the pump in response to the liquid pressure of the material being pumped. One approach, which has been used when an electrical motor is used to drive a pump, is to place a liquid pressure switch in the liquid delivery line and connect the switch to the electrical motor. When the liquid pressure reaches a predetermined level, the switch actuates and shuts off the power to the motor, thereby shutting down the pump. However, this approach does not work when an internal combustion engine is used to drive the pump, for the irregular stopping and starting of an internal combustion engine is an impractical solution to the problem. In this case, some form of clutch mechanism must be used so that the internal combustion engine may remain operating while the pump becomes disengaged from the engine.
It is desirable to provide a pumping system which may be interchangeably connected to either an electrical drive motor or to an internal combustion engine. Further, it is desirable that the motor control mechanism and power source be a part of the pumping system so that connection to the drive source can be expeditiously accomplished by a simple mechanical connection. This approach enables the pumping system to be manufactured separately from the drive mechanism without regard to the particular drive mechanism which might be selected for particular applications, and the drive motor/pump connection may be interchangeably made in the field, based upon the needs at the time.